Carburetor nozzle



CARBURETOR NOZZLE 4 Sheets-Sheet 1 Filed July 30, 1958 Oct. 25, 1960 J. E. EBERHARDT f 2,957,683

f CARBURETOR NozzLE Filed July 30, 1958 FIG2.

4 sheets-shea 2 Oct. 25, 1960 Filed July 30, 1958 F IG .4.

J. E. EBERHARDT 2,957,683

CARBURETOR- Nozzu:

4 Sheets-Sheet 3 i 4f l 5/ I@ I O IIIIII i f FIG@ 7 145 f 55 7 m fo *n* 139 /e/ l FIG .5.

Q 'r2 FIG. I I

'gl /IVl/f/V/e L2 ./A/wfs E. aff/mear ENGINE SPEED RP. M.

Oct. 25, 1960 A J. E. EBERHARDT 2,957,683

' cARBuREToR NozzLE Filed July 3o, 1958 4 sheets-sheet 4 United States Patent O F CARBURETOR NOZZLE.

James E. Eberhardt, Trenton, Mich., assignor to ACF Industries, Incorporated, 'New York, NX., a corporation of New *Jersey` t Fired July so, use, ser. istpse 9'Claims. (Cl. 2Gb-.441)- This invention relates to means .for supplying air-fuel .mixture to engines. and more particularly'to carburetors tor use on internal combustion enginesl of automotive vehicles.

Prior carburetors fused on present engines in sonne in.- stances have a .tendency to Vsupply too rich a rnixture .Qf air and .fllel .as .the engine speed increases from idling speed at partonen throttle .and tosupply too lean a ininf- .ture when the engine speed has increased beyond a cer,- tain value at `part throttle. This tendency is particularly critical in ycases where the carburetor is oneY that 'is adapted quickly toreach the transfer point wherethe. high speed circuit of the. carburetor ,taires over .frorn the .low speed uit of the carburetor as the engine .speed increases iront. idling speed upon wide-.open throttle... The principal .object of th invention is to. proyideior leaning out `the mixture wh n coming up from idle speed at part throttle to avoid having too rich a mixture during'the initial stage of speed increase. and to 4enrich the rniXture during the linal, stage oi speed increase at part .throttle -to avoid having too lean a ,rnixture during the latter stage- This object is attained, according to the present invention, by providing a convertible bleeder and fuel nozzle between the high speed fuel passage and the mixture, conduitof. the carburetor located within the inlluence. of air ilow through the mixture conduit and so directed in relation to the direction ci air ow that the .air pressure .on the conduit side of the bleed decreases with increase of air velocity in such intanner that, at relatively low engine. speeds and. corresponding relatively low air velocities. air bleeds .frorn .the conduit. into the. fuel passage. with the result that the mixture is leaned out. and, atrelatively high. engine speeds and corresponding relatively high air velocities, the bleeder. converts to a. fuel .nozzle and discharges ,fuel from the fuel passage into the mixture conduit, with the result that the supplementary nozzle action of. the bleeder causes the rnia'tnre to be enriched. Other objects and features will be in part apparent and. in part pointed out hereinafter- AThe invention accordingly comprises the constructions v"hereinafter, described, the scope .of the invention being indicated in the following claims.

'In the accompanying drawings. in which one of various possible embodiments of the invention is illustrated,

` Fig. l. is` a plan view of a tour-barrel. carburetor in which the invention `is incorporated;

Fig. 2 is a vertical section taken on line z -Zot'l Fig. 1;

Fig. 3 is a vertical section taken on line 3 3 of Fig. l;

Figs. 4, andS are vertical sections taken on lines 4 and 5 5, respectively, of Fig. l.,l on a reduced scale as relatedto' Fig.` l; Fig. 6 is a `horizontal half-section taken on line 6 6 of Fig. 3, appearing as if the cover for thercarburetor were removed;

Fig. 7 is an enlarged plan view perse of'a special nozzle .used in the `carburetor for incorporating the invention atherein, being viewed on line 1" 7` of Fig. y2, Vand with parts .broken away and shownpinsection;

2,957,683 Patented Get. 25, 1960 Figs. 8 and 9 are vertical sections taken on lines 8 3 `and 9 9, respectively, of Fig. 7;

Fig. l() is a bottom plan view of Fig. 7; and,

Fig. 11 (Sheet 3) is a chart illustrating certain mixture ratio/engine speed characteristic curves.

Corresponding reference characters indicate corresponding parts i throughout the several views of the drawings. v

Referring yto the drawings, the invention is illustrated in its application to a multi-barrel multistage carburetor of the type commonly referred to a` four-barrel carburetor. Asshown, the carburetor comprises a main body casting 1 which. is forrned to provide a `throttle body section 3e and a iloat bowl section 5 onv the throttle body section. The throttle body section d. has lugs 7 for attachment to the intake` manifold. of the engine on which the carburetor is used1 The lloat bowl section is generally of rectangular shape in. plan.. its side walls being designatedv 9 and 1.1 and its end walls being designated `1,3 and 1 5. Partitions 17 and 19 extend between the side walls 9 and 1.1 adjacent the end walls 13- and 1S to define two iioat bowls 2;1. and 2.3, one at each end of the fuel bowl section 5,. 'Each of the partitions 17 and 19 'has aycentral inwardly directed offset 2 5 providing a vertically extending recess s uh as indicated at 27. A partition 29 extends between offsets 125 dividing the space bounded 'by side walls. 9 and 11 and partitions 17 and 1.9 into a primary section 31 and a secondary section 3 3. The primary section is iornied to provide two side-by-side primary mixture conduits or barrels 35 and 37, and the secondary .section is formed to provide two side-by-side secondary mixture conduits or b'arrejlsrl3j9 ,and 41. Each primary barrel is formed as a venturi. Secured to the top ot" the fuel bowl section is a float bowl cover 43 formed to provide a circular air horn 4 5. The horn has a diametrical partition 47 coplanar with partition 29 dividing it into a primary air inlet '31a above section 31 and a secondary air4 inlet 33a ,above section 33.

The cover d3 has a fuel inlet 49 and an inlet passage 51 connecting the inlet to the two float bowls 21 and 23. Entry of fuel yto the bowls from passage 51 is controlled by two float valves 53, one for each bowl (see Fig. 4). Each of these valves is controlled by a float 55 in the respective bowl. The valves and oats may be of any suitable construction, their details not being critical so far as this invention is concerned. The bowl 21 supplies the barrel 35 and the bowl 23 supplies the barrel 37 via identical systems. Only the system for barrel 35V will be described, and it will be understood that the system for barrel37 isidentical. y

Barrel 35 has an upwardly facing shoulder 57 at the side thereof toward the respective lfloat bowl 21 (see Figs. 2 and 3).l Extending down from this shoulder is a vertical well 59. The casting 1 is formed with a passage. v61 from the bottom of recess 27 of bowl l21 to the bottom of the well 59. This passage is formed by drilling a vertical hole 63 extending down from the bottom of recess 27 to an intersection with an inclined hole 6 5 drilled f rorn the bottom of throttle body section 3 to the lower end` of the well, The outer end of hole 65 is plugged as indicated at 67. Threaded in the upper end of hole 63 is va metering jet 69. A metering rod 71 extends down in recess 27 and through the jet from a vacuum-responsive cont-rol contained Ain the float bowl section 5 under a cap 73. The metering rod and control are of known construction and need not be further described, details thereof not being critical so far as this invention is concerned. lt will be understood that the control for the rod acts to move themetering rod up and down in responsie to change in in talge manifold vacuum, for high speed fuel metering. l'

Shoulder 57 serves to support a nozzle body 7-5 (see Figs. 2, 3 and 5-10) at the upper end of the primary barrel. This body comprises a casting formed to provide a head 77, and arm 79 extending horizontally from the head, and a boost venturi 81 at the outer end of the arm. The head is secured on the shoulder l57 as by screws 83. A hole 85 is drilled through the head 77 and the arm 79 from the outside of the head to open into the boost venturi 81. The outer end of this hole is closed as by a welch plug 87. The hole 85 is angled upward from the outside of the head to the boost venturi 81. A hole 89 is drilled up from the bottom of the head to an intersection with angled hole 85. A hole 91 of smaller diameter than hole 89 is drilled to extend up from angled hole 85 coaxial with the hole 89, and to an intersection with a horizontally extending hole 93 drilled in head 77 adjacent its upper end (see Fig. 9).

A fuel tube 95 has its upper end pressed in hole 89 and extends down into the well 59. An idle fuel tube 97 of smaller diameter than tube 95 has its upper end pressed into hole 91 and extends down within the tube 95. Idle tube 97 has a restricted lower end 99 which extends down below the lower end of tube 95. A nozzle tube 1 s pressed in the angled hole 85, extending from hole 89 through the arm 79 into the venturi 81. In accordance with this invention, nozzle arm 79 is formed with a downwardly extending tubular projection 103, the passage in which is designated 105. Nozzle tube 101 has an annular peripheral groove 107 registering l with passage 105 and a hole 109 in the bottom of the groove registering with passage 105. Hole 109 is of smaller diameter than the inside diameter of nozzle tube 101 and of smaller diameter than pasage 105. The space 111 between tubes 95 and 97 and the nozzle tube 101 provides a high speed fuel passage from the well 59 to boost venturi 81. Hole 109 and passage 105 provide a restricted bleeder for this high speed fuel passage 111, 101 within the influence of the primary barrel 35 (the main venturi) where the action of the bleeder is subject to air ow through the carburetor, as will be made clear.

Idle tube 97 is part of a low speed circuit for delivering fuel at low speed operation to idle port 113 (see Fig. 5) in the primary barrel. This low speed circuit includes holes 91 and 93 in the nozzle head 77. Head 77 has a vertical hole 115 (see Fig. 9) extending up from its bottom with a restricted air bleed hole 117 through the upper end of the head. Hole 93 has a restricted economizer passage 119 extending from its inner end into the vertical hole 115. An air metering plug 121 is pressed in the outer end of hole 93. Air is by-passed from the air horn 45 through and metered by plug 121 into the hole or passage 93. Air bleeds into the vertical hole 115 from the air horn through bleed hole 117 to lean the mixture delivered through the economizer 119. The vertical hole 115 is aligned with a hole extending down from shoulder v57 which constitutes part of a passage 123 for flow of fuel-air mixture from hole A115 to the idle port 113, the flow being adjustable by means of the usual idle adjusting screw 125.

Head 77 has a second vertical hole 127 (see Fig. 8) in the upper end of which is pressed a nozzle bleed tube 129 having a restricted upper end 131. The bottom of the head is formed with a slot 133 connecting the lower end of the vertical hole 127 and the hole 89 for communication between the hole 127 and the well 59. Fuel tube 95 has a hole 135 adjacent its upper end directed toward the slot 133. This allows air to bleed into the space 111 between tubes 95 and 97.

Each of the primary barrels 35 and 37 has the usual primary throttle valve 137 (see Figs. 2 and 5) at its lower end, the two primary throttle valves being tixed on the usual primary throttle shaft 139 journalled in the throttle body section 3. In the primary air inlet portion31a of the air horn 45 is the usual choke valve 141, -the usual choke control being indicated at 143 in Fig. 1. The carburetor has the usual accelerator pump such as indi- 4 cated at 145 in Fig. 4 for supplying fuel to the primary barrels in response to opening of the primary throttles via a pump discharge jet cluster indicated at 147 in Figs. 1, 2 and 6. Vents such as indicated at 149 are provided for venting the oat bowls to the interior of the air horn 45, and vent holes such as indicated at 151 are provided for venting the float bowls to the outside.

At the upper end of each secondary barrel 39 and 41 is a venturi cluster 153 having a fuel nozzle 155 supplied with fuel from the respective float bowl via a pas-` sage part of which is indicated at 1'57 in Fig. 5. Each secondary barrel has the usual secondary -throttle valve 159 at its lower end, the two secondary throttle valves being fixed on the usual secondary throttle shaft 161 journalled in the throttle body section 3. Each secondary barrel also has the usual velocity valve 163 therein, the two velocity valves being xed on shaft 165 which carries weights such as indicated at 167 for biasing the velocity valves closed.

At the ends of the carburetor, as shown in Fig. l, are the usual mechanisms for controlling the primary throttle shaft 139 and the secondary throttle shaft 161. It will be understood that these mechanisms include such components -as'the usual actuating lever 169 fixed on one end of the primary throttle shaft 139 adapted for connection of an actuating rod for actuating the primary throttle shaft from the usual pedal, the usual fast-idle cam 171 connected as indicated at 173 to the choke valve shaft 175, and the usual mechanism such as indicated at 177 for operating the secondary throttle shaft 161 to open the secondary throttle valves 159 on opening of the primary throttle valves a predetermined amount. Details of these mechanisms are not critical insofar as this invention is concerned, and further detailed description thereof is therefore omitted.

Operation is as follows:

Assuming that the engine is idling, and that the primary throttle valves 137 are partly opened to come up off idling, fuel is supplied to each of the primary barrels 35 and 37 via the high speed circuit for each of these barrels including space 111 between tubes 95 and 97 and the nozzle tube 101 when the engine speed increases to the point where the velocity of yair flowing through the barrels is suicient for the high speed circuit to take over from the low speed circuit. At this point, the air velocity is still relatively low, and the pressure at the mouth of bleeder projection 103 (which is directed downstream relative to the direction of air flow) is accordingly relatively high with the resul-t that air from the primary barrel (the main venturi or mixture conduit) bleeds through projection 103 and the bleeder hole 109 into the nozzle tube 101 to lean the mixture of air and fuel supplied to the engine. After the high speed circuit has taken over and upon further increase in engine speed with resultant increase in the velocity of air flowing through each primary barrel, the pressure at the mouth of bleeder projection 103 decreases, and the bleeding 0f -air into the nozzle tube 101 through bleeder hole 109 decreases. Eventually, a state of balance is reached where bleeding of air through hole 109 into the nozzle tube 101 ceases. Then, upon further increase in engine speed with resultant further increase in the velocity of air flowing through each primary barrel and further decrease in the pressure at the mouth of bleeder projection 103, fuel is discharged from nozzle tube 101 through bleeder hole 109 and projection 103 into the primary barrel to enrich the mixture of air and fuel supplied to the engine. As the engine speed and air velocity continue to increase, and the pressure continues to decrease, fuel is discharged through hole 109 at an increased rate.

The solid line curve A in Fig. 11 is the part-throttle mixture ratio/engine speed characteristic curve of the above described carburetor having bleeder 109, 103. Curve W is the wide-open throttle mixture ratio/engine speed characteristic curve. The horizontal coordinates in assises sl Fig. 11 represent'engine speed in revolutions perminute. The vertical coordinates represent mixture ratio in terms of pounds of air to pounds of fuel. As appears -from curve A the mixture ratio increases (the mixture becomes leaner) as enginespeedincreases in-comingup from idling at `part throttle until the speed reaches about V1800 r.p.rn., at Which'point'the mixture is the socalled economy Vmixture, Vthen 'levels off and remains substantially constant-'until engine speed increases to about 2600 r.p.m. At this point, aswill be understood, the metering rods 71 `are actuatedy to enrich the mixture to obtain the so-called power mixture (about l2 to 1` ratio). This power mixtureratio isA fully` attained at about 3000 r.p.-m., as shown, and is maintained substantially cons-tant with further increase in speed. It' will' be-observed that theA mixture ratio vcomes down relatively sharplyV at part throttle to the economy mixture, thisl being -dueto the action of bleeder 109, 103` to lean the mixture when the Yhigh speed circuit comes into operation in comi-ng oft idle. The power mixture ratio' is maintained lsubstantially constant with increase in, speed from 3000 r.p.m. due to thefaction of the bleeder 109, 103 to enrich the vmixture'at the higher engine speeds (and higher air velocities). v

In contrast, Fig. l1 shows dotted line curve B representing the part-throttle mixture ratio/ engine speed characteristic 4curve of the carburetor as it would 'be without any bleed. It will be observed that this curve starts atteningout at about 1200 r.p.m. and lies above curve A from about 1200 r.p.m. to about 2000 r.p.m., illustrating that themixture is too rich in this region. Then, this curve droops down below curve A, comes upto the power mixture ratio beyond curve A, and droops off again, illustrating that the mixture-is too lean at lhigher speeds. Dotdash line curve C represents wha-t would be the partthrottle mixture ratio/engine speed characteristic curve for a carburetor with. a bleeder that functioned only to lean the mixture in coming cfr idle, but incapable of functioning, to enrich the mixture at higher speeds by bleeding in `fuel athigher speeds. It will be observed that this sags off at higher speeds like curve B.

In view of the above, it will be seen that the several objects ofthe invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the Scope of the invention, it is intended that al1 matter contained in lthe above description or shown in the accompanying drawings shall be interpreted as illustrative and Vnot in a limiting sense.

I claim:

1. A carburetor having a main venturi, a nozzle for flow of fuel from a source thereof into the main venturi, said nozzle having a boost venturi at the end thereof in the main venturi, and said nozzle having a bleeder located outward of the boost venturi and within the main venturi, said bleeder being directed downstream relative to the direction of air flow through the main venturi and thereby adapted to act in response to velocity of air flowing through the main venturi to bleed air from the main venturi into the nozzle at relatively low air velocities and to admit fuel from the nozzle into the main venturi at higher air velocities.

2. A carburetor having a main venturi, a nozzle body comprising an arm extending into the main venturi and a boost venturi at the end of the arm, said nozzle body having a fuel passage extending through said arm to said boost venturi, said fuel passage being in communication with a source of fuel, and said arm having a bleeder directed downstream relative to the direction of air ow through the main venturi and thereby adapted to act in response to velocity of air flowing through the main venturi to bleed air from the main venturi into said passage at relatively low air velocities and to admit fuel from the passage into the main venturi at higher air velocities.

'3Q A carburetor having a main venturi, said mam venturi having-an upwardly facing shoulder at one side thereof, a nozzley body` comprising a head secured on said shoulder, an arm 'extending' from the headinto the main venturi, and a boost venturi at the end of the arm, said' nozzle body having a fuel passage extending from said head through said arm to said boost venturi, said fuel passage being in communication with a source of fuel, and said arm having a downwardly directed bleeder adapted to act in response to velocity of air owing through the main venturi to bleed air from the main venturi into said passage at relatively low air velocities and to admit fuel from said passage into the main venturi at higher air velocities.

4. A carburetor having a float bowl section formed to provide a float bowl and a main venturi, with an upwardly facing shoulder at one side of said mainventuri, a nozzle body comprising a head` secured on said shoulder, an arm extending from the head into the main venturi and a boost venturi at the end Yof the arm, said nozzle body having a passage extending from the head through vsaid arm to said boost venturi, said oat bowl section having a well extending down from said shoulder, a fuel tube extending down vfrom said head into said well, said tube opening at its upper end to said passage, said float bowl section being passaged for ow of fuel from the float bowl to said Well, a nozzle tube in said passage extending into said boost venturi, said arm having a downwardly extending tubular projection, and said nozzle tube having a hole therein smaller than the internal diameter of the nozzle tube in communication with said tubular projection.

'5'. A carburetor having a float bowl section formed to provide a float bowl and a main venturi, with an upwardly facing shoulder at one side of said main venturi, a nozzle body comprising a head secured on said shoulder, an arm extending from the head onto the main venturi and a boost venturi at the end of the arm, said nozzle body having a passage extending from the head through said arm to said boost venturi, said oat bowl section having a Well extending down from said shoulder, a fuel tube extending down from said head into said well, said tube opening at its upper end to said passage, said float bowl section being passaged for ow of fuel from the oat bowl to said well, a nozzle tube in said passage extending -i-nto said boost venturi, said arm having a downwardly extending tubular projection, and said nozzle tube having an annular peripheral groove registering with said projection and a hole in the bottom of the groove smaller than the internal diameter of the nozzle tube.

6. A carburetor having a oat bowl section formed to provide a float bowl and a main venturi, with an upwardly facing shoulder at one side of said main venturi, a nozzle body comprising a head secured on said shoulder, an arm extending from the head into the mai-n venturi and a boost venturi at the end of the arm, said nozzle body having a passage extending from the head through said arm to said boost venturi, said float bowl section having a well extending down from said shoulder, a fuel tube extending down from said head into said well, said tube opening at its upper end to said passage, said oat bowl section being passaged for tlow of fuel from the oat bowl to said well, a nozzle tube in said passage extending into said boost venturi, said arm having a downwardly extending tubular projection, said nozzle tube having a hole therein smaller than the internal diameter of the nozzle tube in communication with said tubular projection, an air bleed passage extending through said head to said well, and said fuel tube having a hole therein adjacent its upper end for bleeding air from said air bleed passage into said fuel tube.

7. A progressive feeding type of carburetor having a body, a mixture conduit extending through said body,

venturi means in said mixture conduit, a main fuel nozzle opening into said venturi means in a zone of comparatively high pressure drop in the free stream air ow through said mixture conduit, a source of fuel, a fuel passage connecting said source of fuel with said fuel nozzle, and a convertible bleeder and fuel nozzle connected with said fuel passage between said fuel nozzle and said source of fuel; said convertible bleeder and fuel nozzle having an outlet located in said mixture conduit in a zone wherein the pressure drop in the free stream air flow through the mixture conduit is less than in said rst zone during initial operation of said main fuel nozzle so as to bleed air into said fuel passage, said outlet for said convertible bleeder and fuel noule being directed with respect to said mixture conduit to be aspirated by the air stream in said mixture conduit, whereby at high air stream velocity through said mixture conduit the flow in said convertible bleeder reverses and fuel is discharged simultaneously from said fuel passage by said bleeder and by said main fuel nozzle.

8. A progressive feeding type of carburetor having a body, a mixture conduit extending through said body, venturi means in said mixture conduit, a main fuel nozzle opening into said venturi means in a zone of comparatively high pressure drop in the free stream air flow through said mixture conduit, a source of fuel, a fuel passage connecting said source of fuel with said fuel nozzle, and a convertible bleeder and fuel nozzle; said convertible bleeder and fuel nozzle having a connection with said main fuel nozzle and an outlet located in said mixture conduit in a zone wherein the pressure drop in the free stream air fow through the mixture conduit is less than in said first zone during initial operation of said main fuel nozzle so as to bleed air into said main fuel nozzle, said outlet for said convertible bleeder and fuel nozzle being directed with respect to said mixture conduit to be aspirated by the air stream through said venturi means, whereby as air stream velocit-ies through said venturi means increase the air bleeding action of said convertible bleeder progressively decreases to zerov and then reverses to discharge fuel simultaneously from said convertible bleeder and fuel nozzle and from said main nozzle.

9. A progressive feed-ing type of carburetor having a body, a mixture conduit extending through said body, venturi means in said mixture conduit, a main fuel nozzle opening into said venturi means in a zone of comparatively high pressure drop in the free stream air ow through said mixture conduit, a source of fuel, a fuel nozzle, a fuel passage connecting said source of fuel with said fuel nozzle, and a convertible bleeder and fuel nozzle connected with that fuel passage between said fuel nozzle and said source of fuel; said convertible bleeder and fuel nozzle having an outlet located in said mixture conduit in a zone wherein the pressure drop in the free stream air flow through the mixture conduit is lessl than in said first zone during initial operation of said main fuel nozzle so as to bleed air into said fuel passage, but increases with increased air ow through said mixture conduit, said outlet for said convertible bleeder and fuel nozzle being directed with respect to said mixture conduit to be aspirated by the air stream in said conduit, whereby the flow in said convertible bleeder and fuel nozzle progressively decreases with increased air ow velocities through said mixture conduit to reduce the delivery from said main fuel nozzle during initial operation thereof in a retrogressive manner and subsequently reverses to act as a supplementary fuel nozzle at still higher air inflow velocities through said mixture conduit.

References Cited in the file of this patent UNITED STATES PATENTS 2,215,683 Wirth Sept. 24, 1940 2,568,987 Brunner Sept. 25, 1951 2,676,004 Bimberg Apr. 20, 1954 2,771,282 Olson et al. Nov. 20, 1956 

